THE HEREDITY OF RICHARD ROE. 133 
to appropriate stimulation is that which especially dif- 
ferentiates high animal organisms from low animal or- 
ganisms., 
“Without this power and the plasticity which results 
from it the multitudinous parts of high animals could 
not well be co-ordinate, and therefore without it their 
evolution could scarcely have been possible. Indeed, it 
is not too much to say, so vitally important is this 
power to the higher animals, that as regards them the 
chief aim (if I may use the expression) of natural se- 
lection has been to evolve it.” * 
One more element, likewise of doubtful value, must 
be added to the inventory of Richard 
Prenatal Roe. This is the element of prenatal 
influences. ‘ ; 
influence on the part of his mother. 
In the process of evolution the development of the 
female has brought her to be more and more the pro- 
tector and helper of the young. She gives to her prog- 
eny not only her share of its heredity, but she becomes 
more and more a factor in its development. 
In the mammalia the little egg is retained long in 
the body and fed, not with food yolk, but with the 
mother’s blood. The “gate of gifts” is not closed with 
the process of fertilization as it is in the lower forms. 
If the help of favourable environment can be counted 
as a gift, this gate is not closed at birth nor so long as 
the influence of the mother remains. By the growth of 
the human family the parental environment becomes a 
lifelong influence. The father as well as the mother 
becomes a part of it. In Walt Whitman’s words: 
‘His own parents (he that had fathered him and she that had 
conceived him in her womb and birth’d him), 
They gave this child more of themselves than that, 
They gave afterward every day, they became part of him.” 
* Archdall Reid, Science, December 17, 1897, p. got. 
